RRDNS is written in Go and uses Go’s time.Now() function to get the time. Unfortunately, this function does not guarantee monotonicity. Go currently doesn’t offer a monotonic time source (see issue 12914 for discussion).

修正的方式是針對時間回朔時處理：

In this patch we allowed RRDNS to forget about current upstream performance, and let it normalize again if time skipped backwards.